[BUGFIX] Indexer does not update the FileObjects

If the Indexer updates metadata during runtimer (after a file object)
has been created, the file object itself is not updated.

This leads to possible errors with image rendering, if files are to be
shown which have not been indexed before.

Releases: 6.2
Resolves: #53772
Change-Id: I70be5ebefe1e00e903694a576847fa8fba167461
Reviewed-on: https://review.typo3.org/27690
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters